How to copy child object in array
Boolean Union Modifier
Modifiers alter the vertices of the modified mesh.

Hide the child frame object and &quot;join&quot; it to the wall mesh using a boolean union operator before the array modifier(s).
Example image small cube &quot;Cube.001&quot; child of arrayed big cube &quot;Cube&quot;.
Re materials
Join objects (boolean) with different materials
Note: this is not inheritance, (the object need not be a child) the modifier alters the mesh of the original.